[SOLVED] MSI Z590 Pro Wifi - Ethernet Unrecognized Above 100Mbps Full-Duplex

Jan 17, 2022
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MSI Z590 Pro Wifi - Ethernet Unrecognized Above 100Mbps Full-Duplex

System Details:
MSI Z590 Pro Wifi - 2.5G LAN Port
Intel(R) Ethernet Controller (3) I225-V (1.0.2.14)
Windows 10 Pro 19043.1466
Xfinity Gigabit Internet Plan

Routers Tested:
Issue:
Network status presents "Not connected" when Speed & Duplex is set > 100Mbps. No Ethernet light shows on the port when set above 100Mbps.



Description:
My issue started after I installed a new MSI Z590 Pro Wifi motherboard. Same ethernet cable and router as before, but now was unrecognized with my AT&T U-verse router. Was able to regain connection after force setting speed & duplex to 100Mbps.
Working at 100Mbps Full Duplex (Green and blinking orange light on Ethernet when at 100Mbps):

  • 10 Mbps Full Duplex [WORKING]
  • 10 Mbps Half Duplex [WORKING]
  • 100 Mbps Full Duplex [WORKING]
  • 100 Mbps Half Duplex [WORKING]
  • 1.0 Gbps Full Duplex [BROKEN]
  • 2.5 Gbps Full Duplex [BROKEN]
  • Auto-Negotiation [BROKEN]
Trouble Shooting
  • I've tried 3 different ethernet cables (Cat5e, Cat5e, Cat7 brand new)
  • Different Ethernet ports on the router (tried multiple different routers at separate households)
  • Reinstalling Intel Ethernet Drivers (Both from the motherboard's provided disk and from the online download)
  • Reset computer entirely, installed drivers back from scratch
  • Updated BIOS
*WiFi works without issue (near gigabit speeds)
*No VPNs or VMs
*Ethernet cable is 20ft
*Does not appear anything is blocking the Ethernet port on either side. Clean click when inserting ethernet cable:
 
Last edited:
In general you want to always run auto. The problem comes is the router is running auto and most router do not have a option to run anything else. There is a hardware based test/negotiation that is done when you have it set to auto. If the router expects to get certain voltages/signals and does not get them many times
it will drop to a random state. Used to be they always defaulted to 10mbps half duplex. Some chipset are not so stupid but this is one of those things that you really don't want to be digging in chipset tech documents to determine what happens when both sides are not auto.

In your case you have pretty much eliminated all the common things. I am going to bet if you used a cable that only had 2 pair or if cut one of the brown/blue pairs it would auto negotiate to 100mbps. A bad cable where one pair is defective is extremely common cause but you have tried many cables.

This leaves the port in the machine. You can check that none of the small wires inside the port appear damaged. They are almost impossible to fix even if you were to find one. It is more likely something has failed in the electronics in the port....but not completely so it still kinda works.

If you have the room I would put in a pcie ethernet card. A USB3 based ethernet card would be acceptable if you can't use pcie. USB uses slightly more cpu resources than pcie.

There are massive amounts of problems with the 2.5g chipsets but I don't think what you are describing is one of them.
 
In general you want to always run auto. The problem comes is the router is running auto and most router do not have a option to run anything else. There is a hardware based test/negotiation that is done when you have it set to auto. If the router expects to get certain voltages/signals and does not get them many times
it will drop to a random state. Used to be they always defaulted to 10mbps half duplex. Some chipset are not so stupid but this is one of those things that you really don't want to be digging in chipset tech documents to determine what happens when both sides are not auto.

In your case you have pretty much eliminated all the common things. I am going to bet if you used a cable that only had 2 pair or if cut one of the brown/blue pairs it would auto negotiate to 100mbps. A bad cable where one pair is defective is extremely common cause but you have tried many cables.

This leaves the port in the machine. You can check that none of the small wires inside the port appear damaged. They are almost impossible to fix even if you were to find one. It is more likely something has failed in the electronics in the port....but not completely so it still kinda works.

If you have the room I would put in a pcie ethernet card. A USB3 based ethernet card would be acceptable if you can't use pcie. USB uses slightly more cpu resources than pcie.

There are massive amounts of problems with the 2.5g chipsets but I don't think what you are describing is one of them.
 
Jan 17, 2022
2
0
10
0
In general you want to always run auto. The problem comes is the router is running auto and most router do not have a option to run anything else. There is a hardware based test/negotiation that is done when you have it set to auto. If the router expects to get certain voltages/signals and does not get them many times
it will drop to a random state. Used to be they always defaulted to 10mbps half duplex. Some chipset are not so stupid but this is one of those things that you really don't want to be digging in chipset tech documents to determine what happens when both sides are not auto.

In your case you have pretty much eliminated all the common things. I am going to bet if you used a cable that only had 2 pair or if cut one of the brown/blue pairs it would auto negotiate to 100mbps. A bad cable where one pair is defective is extremely common cause but you have tried many cables.

This leaves the port in the machine. You can check that none of the small wires inside the port appear damaged. They are almost impossible to fix even if you were to find one. It is more likely something has failed in the electronics in the port....but not completely so it still kinda works.

If you have the room I would put in a pcie ethernet card. A USB3 based ethernet card would be acceptable if you can't use pcie. USB uses slightly more cpu resources than pcie.

There are massive amounts of problems with the 2.5g chipsets but I don't think what you are describing is one of them.
Thanks, I appreciate your reply. I had assumed as much and had already ordered a pcie ethernet card yesterday, was just hoping for some better news. I had originally installed the IO plate with the little tab for the ethernet facing the wrong way. Could that may have caused my issue?
 
You could look to see if a wire is bent internally in the jack but it is rare and not easily fixed. The cables may not have fit properly before you fixed the shield but it should have not done any damage. Ethernet ports are pretty tolerant of stuff you can short the pins together and it cause no damage.
 

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